1. Field of the Invention
This invention relates to a method of adjusting scanner photoelectric module, particularly to a method of the adjusting the scanner photoelectric module (lens and charge-coupled device) to the favorable position and MTF through a change of the reference pattern.
2. Description of the Prior Art
Refer to FIGS. 1-4, which illustrate a method and system of adjusting the charge-coupling component and lens of the scanner module as specified in the Patent Publication No. 316969 of the Republic of China.
In FIG. 1, a scanner module 22 is first arranged an adjusting assembly platform 24 when lens 30 and the charge-coupled device 20 are adjusted. The charge-coupled device 20 is placed in front of the scanner module 22 through a holder 28, as shown in FIG. 2A. The holder 28 can move at X and Y directions and rotate at xcex8 direction. The scanner module 22 further comprises: a light source 39, reflective mirrors 31, 33, and 35, and lens 30, as shown in FIG. 2B.
FIG. 3 is a reference pattern for adjusting the positioning. In the figure, the triangular patterns 422 and 45 determine the horizontal status of the charge-coupled device; the lateral straight lines 40 determine the scan margin of the charge-coupled device, and the parallel lines 44 determine the MTF of the scanner optical module 22 at the scan direction. Refer to FIG. 4 for the image signals the charge-coupled device module obtains in accordance with said reference pattern. Therein, x corresponds to the distance from the origin of the coordinate to the left straight line 40, y1 and y2 correspond to the sectional distance from the triangles 42 and 45 to the scan line, while f corresponds to the parallel line 44. When x is too large or small, it denotes the reference pattern is not projected to the center of the scan range of the charge-coupled device 20; therefore, adjustment of the charge-coupled device 20 needs to be made at X direction. When the average of y1 and y2 is too large or small, it denotes the position is too low or too high for the charge-coupled device 20 to scan the reference pattern (when the scan position is high, the sectional distance from the triangles 42 and 45 to the scan line increases; conversely, when the scan position is low, the sectional distance from the triangles 42 and 45 to the scan line decreases). Therefore, adjustment of the charge-coupled device 20 needs to be made at Y direction. When y1xe2x89xa0y2, it denotes the charge-coupled device 20 scan the reference pattern slantingly (when the scan lines incline, the triangles 42 and 45 will scan the top and bottom parts or the bottom and top parts to make the corresponding sectional distances uneven). Therefore, adjustment of the charge-coupled device 20 needs to be made along xcex8 direction to resume to the horizontal status.
Moreover, the MTF value can be obtained in accordance with f signal of the reference signal. However, since the MTF value is represented in the absolute value, only the minimum at the X direction can be adjusted. When the optimal MTF value does not appear at X direction and Y direction, incidents such as good MTF at X direction but bad MTF at Y direction, or bad MTF at X direction but good MTF at Y direction might result.
Further, it becomes cumbersome to determine the margins and the horizontal status of the two patterns (straight lines and triangle), respectively. Also, mistakes may incur as a result of determining the margins with straight lines.
Accordingly, the primary object of this invention is to provide a method of adjusting scanner photoelectric module, the reference pattern being used comprises a straight line pattern vertical to the scan direction and a straight line pattern diagonal to the scan direction. Consequently, the MTF at either X direction or Y direction can be simultaneously read out by the signal corresponding to the charge-coupled device 20, and the optimal MTF can be rendered in combination with the adjustment of the MTF at X direction and Y direction to the minimum.
Moreover, this invention can also combine straight lines and triangular patterns of the reference pattern for obtaining the scan margins and the horizontal status of the charge-coupled device with the same pattern, so misreading due to extremely thin straight lines can be avoided.
In the method of adjusting scanner photoelectric module, a reference pattern is projected to the charge-coupled device through a lens for generating image signal corresponding to the charge-coupled device. The lens and the charge-coupled device perform adjustment in accordance with the obtained image signal to improve MTF value and the magnification (or zooming) ratio. This invention is characterized in providing a block at each of the two sides of the scan width of the reference pattern and two sets of line patterns between the scan widths of the reference pattern. The two blocks (such as right angle blocks) are increasing/decreasing in their width and are symmetrical, and have a side at the vertical scan direction, for determining the margins and the horizontal status of said scanner photoelectric module, for determining the margins and horizontal status of the scanner photoelectric module and for preventing misjudgment of straight lines.
Moreover, this invention also provides a device of adjusting scanner photoelectric module, wherein, the reference pattern comprises in its scan width a straight line pattern vertical to the scan direction, a slant line pattern and a width-increasing/-decreasing, symmetrical block and a side vertical to the scan direction on each of the two sides of the scan width. The reference pattern is projected to the charge-coupled device through the lens of the scanner photoelectric module for generating an image signal corresponding to the charge-coupled device. The driving device then adjusts the position and the MTF of the lens and the charge-coupled device in accordance with the image signal.